Objective: To explore the antinociceptive effects of combination of ketorolac with different opioids in central and visceral nociception. Methods: Tail flick method and writhing method were used as animal models of central and visceral nociception, respectively. Results: Coadministration of subeffective doses of combination of ketorolac (10mg/kg) with different opioids (morphine 1.5mg/kg, pethidine 10mg/kg, fentanyl 20__ampersandsignmicro;g/kg, buprenorphine 0.05mg/kg, and tramadol 10mg/kg) increased pain threshold (percentage analgesia) in tail flick method and decreased the number of writhes (increased percentage inhibition) in writhing method significantly. Ketorolac fentanyl combination in subeffective doses was more effective in enhancing the pain threshold, producing highly significant antinociceptive effect (93.33% analgesia) in tail flick method whereas the combination of subeffective doses of ketorolac and tramadol produced highly significant effect (88.99% inhibition) in writhing method. Conclusion: The present study suggests that coadministration of ketorolac with fentanyl produces the maximum analgesia in central pain model whereas ketorolac tramadol combination is more effective in visceral pain. In clinical practice this would allow use of combination for effective analgesia according to the type of pain.